<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <button>按钮1</button>
    <button>按钮2</button>
    <button>按钮3</button>
    <button>按钮4</button>
    <button>按钮5</button>
    <script>
        var btns = document.getElementsByTagName('button')
        for (var i = 0; i < btns.length; i++) {
            btns[i].onclick = changeColor
        }
        function changeColor() {
            for (var j = 0; j < btns.length; j++) {
                if (btns[j] === this) {
                    this.style.backgroundColor = 'pink'
                } else {
                    btns[j].style.backgroundColor = ''
                }

            }

        }

    </script>
</body>
</html>